Mechanical remote shift arrangement

ABSTRACT

A mechanical remote shift arrangement for shifting gears of a motor vehicle transmission with a remote shift bracket fastened to the vehicle, equipped with a shift lever, a shift rod array consisting of shift rods and articulations in the form of universal joints which transmit the shift motions to the shift mechanism. By supporting the shift rod array in the vehicle frame by means of idler arms, a shift mechanism with a high degree of efficiency is attained despite multiple deviation of the shift rod array from a straight line. The idler arms of the idler arm bearing are fastened to the vehicle frame either journaled in ball bearings via a bearing bracket, or via tie rod ends, and have, for incorporation into the shift rod array, either on a fastening flange of a universal joint or on the fastening flange of a shift rod, a tie rod end, which enables the oscillating motion of the idler arm as well as the rotary motion of the shift rod array.

CROSS REFERENCE TO RELATED APPLICATION

This application is a National Phase application of PCT/EP86/00673,filed Nov. 21, 1986, and based upon Luxembourg application Ser. No.PCT/EP85/00652 filed Nov. 28, 1985 under the International Convention.

FIELD OF THE INVENTION

Our present invention relates to a remote shift arrangement for theshifting of gears in motor vehicle transmission of the type which has aremote shift bracket fastened in the vehicle equipped with a shiftlever, a shift rod array consisting of shift rods and articulations,preferably universal joints, which transmit the shift motions to a shiftarrangement (e.g. a rotary input shaft) of a shift transmission, andsupport or idler arm bearings for the support of the shift rod array inthe vehicle.

BACKGROUND OF THE INVENTION

Shift arrangements of this type are known, particularly for urban andlong-distance buses, where the shift rod array has to extend overrelatively great distances and where due to obstacles, such as axles,luggage compartments, and gas tanks, the shift rod array must bedeviated in vertical as well as horizontal directions.

The steadily increasing utilization of the space below the floor of suchbuses, particularly long-distance buses, causes an ever increasingnumber of changes of direction in the shift rod array and thus ever morebearing locations. These bearings are preferably plain bearings for theaxial displacement and rotary motion, e.g. with plastic bushings.

With increasing numbers of changes of direction and, therewith, in thenumber of bearing locations, friction also increases and stiffnessdecreases. Such remote shift arrangements require therefore highshifting forces and result in shift arrangements which are hard tooperate and have poor indexing of the selected speeds.

OBJECT OF THE INVENTION

It is therefore the object of the invention to provide an improvedremote shift arrangement which will facilitate operation and increasethe stiffness of the shifting path and thus convenience of shifting andefficiency as well as reliability of shifting with the least possibleconstruction cost.

SUMMARY OF THE INVENTION

This object is achieved in accordance with the invention by providingthe shift rod array with at least one idler arm bearing with an idlerarm movable in the longitudinal direction of the vehicle and which isjournaled on the vehicle (e.g. by a bearing bracket, and tie rod end)and with its head or opposite tie rod end rotatably connected to theshift rod array. This makes possible a limited rotary and longitudinalmotion of the shift rod array.

The use of idler arms for the support of the shift rod array reducesfriction considerably, particularly when the shift rod array, as inmodern long-distance buses, has several articulations and deviatesrelatively greatly from a straight-line connection from the remote shiftbracket to the rotary input shaft on the transmission. Thus, comparativemeasurements of mechanical eficiency of 55% in customary remote shiftarrays have shown improvement to 98% with sliding bearings.

By the use of a generallly known tie rod end, which is manufactured inlarge numbers, in the idler arm, a simple and economical solution isattained, particularly since this tie rod can be used as manufactured,without any modification.

An optimization of efficiency is attained when for the limited excursionof the idler arm from center position (i.e. for shifting of thetransmission into "neutral" or extreme positions for certain speeds),ball bearings are built in between the idler arm and the fixed bearingbracket.

Tie rod ends can also be used as bearing brackets in connection withidler arms formed as forks because the oscillating motion is relativelysmall.

When the connecting cone of the tie rod end is centrally fastened in acorresponding bore in the connecting flange of a universal joint, e.g.in known manner with a nut secured on a threaded stud, then the tie rodend can be passed easily over the open linkage portion. The shift rodscan then be formed in known manner with connecting flanges on both ends,without any aperture for the idler arm. It is also possible, whenparticularly narrow universal joints are to be used, and the tie rod endhas no room within the universal joint, to array the connecting conecentrally on the connecting flange of a shift rod. However, in thissolution an aperture must be provided in the shift rod for the idlerarm.

The shifting rigidity or stiffness and thus the reliability of theremote shift arrangement can be further improved when the remote shiftbracket, preferably constructed with universal joints, is equipped withan amplifying means for the shift motion.

The remote shift arrangement is particularly suited for buses with aremote shift bracket in the driver's cab and the transmission in therear of the vehicle due to the large distance and the relatively manysupports and deviations of the shift rod array from a straight line.However, a remote shift arrangement with idler arms can also be anadvantage for transmissions which are flanged onto an engine in thecenter of the vehicle or for transmissions emplaced to the rear of thedriver's cab and where the shift rod array has several bearings.

Once a universal joint is e.g. welded to a shift rod, then only oneflange connection per articulation is necessary in the shift rod array.

The adaptation of the shift rod array to the vehicle frame and theadjustment operations between the remote shift box and the input shafton the transmission can be simplified considerably when the flangeconnections are formed as clamp connections which fix the shift rodarrays in axial and circumferential direction after the idler arms arefastened to the vehicle frame.

A particularly simple clamp connection is attained by means of a conicalbore in a section of the universal joint which is provided in the areaof the integral flange. A slotted conical clamp ring which lies partlyin this bore is thereby axially displaced by a second flange slid overthe shift rod when the fastening screws are tightened and effectclamping between the universal joint and the shift rod.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features and advantages of the presentinvention will become more readily apparent from the followingdescription, reference being made to the accompanying drawing in which:

FIG. 1 is a partial elevation of an idler arm bearing fastened to auniversal joint;

FIG. 2 is an elevation of an idler arm bearing according to FIG. 1 butshown broken away long a section line II--II of FIG. 3;

FIG. 3 is another elevation of an idler arm bearing according to FIG. 1,but showing a further embodiment of the attachment;

FIG. 4 shows a remote shift bracket in elevation;

FIG. 5 shows a remote shift bracket in a side view in the direction ofthe arrow V of FIG. 4;

FIG. 6 shows a remote shift array in side view;

FIG. 7 shows a remote shift array in plan view;

FIG. 8 shows an idler arm bearing according to FIG. 1 in a furtherembodiment in a partially sectioned elevational view;

FIG. 9 shows an idler arm bearing according to FIG. 8 in section;

FIG. 10 shows a flange connection in longitudinal sectional and

FIG. 11 is a cross section according to FIG. 10 in the area of thesecond flange and the shift rod.

SPECIFIC DESCRIPTION

According to FIG. 1, the idler arm bearing 1 consists of the idler arm12 which is connected to the bearing bracket 11 fastened to the vehicleframe 6 via trunnion 111 and ball bearing 111 (see FIG. 2). The idlerarm 12 has a shaft 121 which a bore and an internal thread, into whichthreaded portion 131 of a tie rod end 13 is screwed, and held by meansof jam nut 133. The conical extension 132 of the tie rod end 13 is heldin a conical bore 223 of the connecting flange 222 of universal joint22--via threaded stud 135 and nut 134. So as to make it possible toposition and fasten tie rod end 13 centrally upon connecting flange 222,the joint section 221 of the universal joint 22 must be of sufficientsize, whereas the second joint section 226 can be made of a common shortconstruction. On the two connecting flanges 222 and 227 of the universaljoint 22, the corresponding connecting flanges 214 and 215 are fastenedby means of connecting screws 23. The tube of the shift rod 21 may bereduced in diameter conically as well as cylindrically in order to holddown the overall diameter of the connecting flanges. The section II--IIof FIG. 2 taken through FIG. 3 shows in particular the arrangement ofthe ball or plain bearings 111 between idler arm 12 and bearing bracket11.

The idler arm bearing according to FIG. 3 is, in principle, constructedlike that of FIG. 1, only the attachment of the tie rod end 13 iseffected not on the connecting flange of the universal joint, but on theconnecting flange 212 of a shift rod 21, where between the connectingflange and the shift rod, a tube section 211 is provided with anaperture 219 for passing the tie rod end 13.

By means of the remote shift bracket of FIGS. 4 and 5, the selection andshift motion is transmitted in known manner from the driver's positionvia shift lever 36, the bracket 37 articulated to the vehicle and via afork 38 to the shift rod array shown in FIGS. 6 and 7 (see DE-PS No. 2159 195).

The ratio of the lever arms or distances for the shift motion betweenthe center of rotation and oscillation 32 on the universal joint ofshift bracket 37, and the center of the universal shifting joint 330designated A, on the one hand, and the center of the shifting joint 330and the support point 34 for 39, designated B, on the other handestablishes the displacement of the rod by the shift lever.

The extension 31 with the connecting flange 35, which is fastened on thefork 38, as in FIG. 4, can engage the rod 39.

From FIG. 6 in elevation and FIG. 7 in plan view, the entire remoteshifting array can be discerned between remote shift bracket 3 with theshift lever 41 in the driver's cab 4 and the transmission 5 with therotary input shaft 51 in the rear of the vehicle. The vehicle frame 6serves to carry the idler arm bearings 1 as well as the remote shiftbracket 3 and the transmission 5. The shift rod array 2 consists of theshift rods 21, whereby the support on the vehicle frame 6 may beeffected via the idler arm bearings 1 according to FIGS. 1 to 3, by wayof example.

FIGS. 8 and 9 show a further embodiment of the idler arm bearing 10,where the idler arm 120 is realized in shape of a yoke. It carries a tierod end 130, which, as already described in FIG. 1, is connectedcentrally in a portion of universal joint 220 either by a conicalconnection or via a cylindrical bore (see FIG. 8).

The idler arm 120 is fastened to the vehicle frame in an articulatedmanner via two further tie rod ends 110, where the tie rod ends 110permit a limited oscillating motion of the idler arm 120 and thus alimited motion of the shift rod array 2 in axial direction.

One of the shift rods 210 is solidly connected to the universal joint220, i.e. with a weld seam 230. Thus very point of articulation oruniversal joint of the shift rod array 2 has only one flange connection225.

In a further embodiment according to FIGS. 10 and 11 in the area of theshift rod bearing array 7 the connection between the universal joint 7and the shift rod 72 is formed as an adjusting and clamping device 73,in order to simplify the axial adaptation of the shift rod array 2 tothe vehicle frame 6, and the centering of the shift rods 72 in theuniversal joint 71.

For this purpose, the section of the universal joint 710 has in the areaof the integral flange 712 a conical bore 711 for the reception of aslotted conical clamp ring 74, and the fastening lugs of flange 712 havetapped holes 713 for the reception of fastening screws 75. The secondflange 721 is not connected solidly to the shift rod 72, but is slidwith its large bore 722 with radial play over the shift rod which isapproximately cut to length.

A slotted conical clamp ring 74 has a cylindrical bore 741 and islikewise slide over the precut end of the shift rod when the universaljoint 71 is slid upon shift rod 72, the radially outer cone 741 comes tolie partly in the conical bore 711 of the universal joint section 710.

When after fastening of the shift rod support 7 to the vehicle frame 6the fastening screws 75 are tightened, then the second flange 721 bearsagainst the face 743 of clamp ring 74, and the shift rod array is fixedin the position preadjusted by the adjusting and clamping device 73. Ifthe cone 742 is fabricated with an angle of about 8° to 9°, then allshifting forces in axial and circumferential direction can betransmitted with this clamping arrangement.

The remote shift arrangement operates as follows: if according to FIG.4, the shift lever is moved, e.g. in the direction of vehicle motion tothe left, then the speeds 1, 3, 5, 7, lying in the direction of motionin the shift array are preferentially engaged. Thereby the motion isredirected about the center of rotation and oscillation 32, and thearticulation for the shift moves opposite the vehicle direction, that isto the right. Thereby the shift rod assembly attached to the connectingflange 35 is likewise moved to the right and all of the supporting idlerarms are swung from the central position shown in FIG. 1 about trunnions112 into a final position about 17° to the right. In cooperation withuniversal joints 22, the provision of ball bearings between bearingbracket 11 and idler arm 12 and the mobility of the conical connection132 on tie rod end 13 facilitate a freely movable translatory motion,which e.g. assures a rotation of the rotary input shaft 51 ontransmission 5, whereby the engagements of the gears occurs in knownmanner via shift rods and idler arms.

For selection of the slots of the shift pattern, the shift leveraccording to FIG. 5 is moved transversely to the vehicle motion, e.g. tothe left, and (therefore) point 33 moves to the right due to rotationabout center of rotation and oscillation 32. Since support point 34remains stationary due to support by support rod 39, there results arotation motion upon shift rod array 2. This rotating motion of theshift rod array 2 leads to a translatory motion of the rotary inputshaft 51 in transmission 5 and thus to the selection of the slots in theshift pattern and (this rotary motion) is essentially unimpeded by thetie rod ends 13 of the idler arm bearings 1.

We claim:
 1. A remote shifting assembly for an automotive vehicle,comprising:a shift lever articulated on the vehicle for speed-selectionmovements; a transmission on the vehicle having a speed-selectionelement moveable in response to displacement of said shift lever andlocated remote from said shift lever; and a shift-rod assembly extendingbetween and operatively connecting said shift lever with saidspeed-selection element for transmitting movements of said shift leverto said speed-selection element, said shift-rod assembly comprising: amember connected to said shift lever and capable of being longitudinallydisplaced in a direction of movement of the vehicle and angularlydisplaced about a longitudinal axis, another member connected to saidelement and capable of being longitudinally displaced and angularlydisplaced in response respectively to longitudinal and angulardisplacement of said member connected to said shift lever, means formingat least one universal joint angularly interconnecting said members andshiftable relative to the vehicle to transfer longitudinal displacementof said member connected to said shift lever to said speed-selectionelement, and at least one idler-arm assembly for supporting saidshift-rod assembly on said vehicle, said idler-arm assemblycomprising:an idler-arm head rotatably connected to said universal jointand permitting rotation thereof relative to said idler-arm assembly, anidler arm carrying said head at one end of said idler arm, and means forpivotally connecting another end of said idler arm to said vehicle forswinging movement about a pivot axis transverse to said direction ofmovement, thereby permitting limited angular and longitudinaldisplacement of said shift-rod assembly relative to said vehicle, saidmeans for pivotally connecting another end of said idler arm to saidvehicle for swinging movement including a bearing bracket fastened tosaid vehicle, a threaded tie rod end connected to said head, a shaftswingably connected to said bracket for swinging movement about saidpivot axis transverse to said direction of movement and threadedly andadjustably receiving said threaded tie rod end, and a conical formationon said head fastened centrally to a section of said universal joint. 2.The remote shifting assembly for an automotive vehicle defined in claim1 wherein said other end of said idler arm is a fork having two pivotsrespectively connected to said vehicle for swinging movement about saidpivot axis transverse to said direction of movement.
 3. The remoteshifting assembly for an automotive vehicle defined in claim 1 whereinsaid shaft is connected to said bracket by a ball bearing.
 4. The remoteshifting assembly for an automotive vehicle defined in claim 1 whereinsaid shaft is connected to said bracket by a plain bearing.
 5. Theremote shifting assembly for an automotive vehicle deifned in claim 1wherein one of said members is a shifting rod formed with a tubularsection into which said head extends laterally.
 6. The remote shiftingassembly for an automotive vehicle defined in claim 1 and wherein thevehicle is a long-distance bus with said shift lever being located at afront of the vehicle and said transmission located at a rear of saidvehicle, said shift-rod assembly comprises a muliplicity of shiftingrods forming said members and having a plurality of said universaljoints between said members between said shift lever and saidtransmission, and each of said universal joints is provided with arespective one of said idler-arm assemblies.
 7. The remote shiftingassembly for an automotive vehicle defined in claim 1, furthercomprising an adjusting, centering and clamping device securing at leastone of said members to said universal joint.
 8. The remote shiftingassembly for an automotive vehicle defined in claim 1 wherein saidadjusting, centering and clamping device comprises:a tubular part onsaid universal joint having a frustoconical bore and a flangesurrounding said bore, a shift rod end forming said one of said membersextending into said bore, a frustoconical clamping ring surrounding saidshift rod end and wedged into said bore, and a further flangesurrounding said shift rod end, bearing axially on said ring and boltedto the flange on said tubular part.